Increased use of radar surveillance has required the provision of camouflage which, when draped over an object readily observable by radar, will defeat radar by providing over the area occupied by the object an apparent impedance substantially matching that of the surrounding terrain. Prior-art workers have been able to provide such camouflage which is effective under woodland and desert conditions, for example, such camouflage being made according to U.S. Pat. No. 3,733,606, issued May 15, 1973, to Sven-Goran Johansson. Since warfare requieres activities in snowy conditions, there has also been a continuing need for camouflage adapted to prevent detection of objects surrounded by snow, and excellent radar transparent camouflage materials are available, following the teachings of U.S. Pat. No. 3,300,325, issued Jan. 24, 1967, to G. W. Lindquist. However, attempts to produce radar defeating snow camouflage in flexible form, suitable to be draped over objects such as tanks, trucks and weapons, have not been generally successful.
Following accepted practices, radar defeating camouflage in flexible form requires use of a flexible web which has been made to present a predetermined impedance to incident electromagnetic ratiation, this usually being accomplished by securing to a fibrous web a multiplicity of tiny metal or graphite fibrils, and covering the fibril-bearing surface of the web with a film of a polymeric material, such as a polyvinyl chloride film cast from a plastisol onto a release web and, after curing to solid form, transferred to and adhered to the fibril-bearing surfce. The fibrous web is typically 0.1-0.25 millimeter thick and the adhered polymer film is typically 0.03-0.07 millimeter thick, so that the optical and physical characteristics of the fibrous web significantly affect the characteristics of the relatively thin finished laminate. When prior-art workers have attempted to provide radar defeating snow camouflage by applying directly to the fibrous web a film of material of a nature such as to match the reflectance characteristics of snow, the finished product had neither the desired physical properties nor the necessary reflectance characteristics. And attempts to apply a snow camouflage film over the polymer film conveniently adhered to the fibrous web have also failed to yield the necessary reflectance characteristics and, further, have resulted in a product which delaminates under low temperature conditions. There is thus a critical need for a satisfactory radar defeating snow camouflage.